Feeding device for a monomer

ABSTRACT

The invention relates to a delivery device for a monomer and comprises an elongate container ( 2 ). This is designed to enclose at least one ampoule containing the monomer. At one end the container ( 2 ) has a connection ( 2   a ) for delivering the monomer to a mixing device, pre-filled with a polymer, for the preparation of bone cement under vacuum. At its other end the container ( 2 ) has a cap ( 2   b ). In the container wall there is an air inlet aperture ( 2   c ). There are also manually actuatable elements for opening at least one ampoule ( 3   a,    3   b ). The cap ( 2   b ) is removable from the container ( 2 ) and has holding elements ( 3 ) designed by means of a positively interlocking engagement to hold fast an ampoule neck ( 3   a   1, 3   b   1 ) inserted into the said holding elements  3 . The said opening elements comprise a knob ( 4 ), which is in threaded engagement ( 4   a ) with a draw rod. The remote end ( 1 ) of the draw rod ( 5 ) extends past the base ( 3   a   2, 3   b   2 ) of the said ampoule(s) ( 3   a,    3   b ) and has a spike ( 6 ) pointing towards the base ( 3   a   2, 3   b   2 ) of each ampoule, it being possible to make the spike penetrate the base ( 3   a   2, 3   b   2 ) by turning the knob ( 4 ).

The present invention relates to a device according to the pre-characterising clause of claim 1.

EP 1 016 452 A2 discloses a delivery device of the generic type. Although this device in itself functions quite satisfactorily, there is a desire to provide a delivery device for a monomer, which is easier to manufacture and handle than this known delivery device.

The object of the present invention is to provide a delivery device that is improved in this respect and this is achieved by the features specified in the characterising part of claim 1.

The invention, which will be explained in more detail below with reference to the drawing attached, furthermore has one or more of the characteristics specified in the subordinate claims.

In the drawing:

FIG. 1 shows an embodiment of a delivery device according to the invention, partially in section,

FIG. 2 shows a detailed view of the holder and penetration element according to FIG. 1, and

FIG. 3 shows a detailed view of the said penetration element.

In the drawing, 1 generally denotes a delivery device for a monomer comprising an elongate container 2, which at one end is provided with a funnel-shaped connection 2 a to a mixing device, not shown in the drawing, and which at its other end has a removable cap 2 b, which preferably has snap elements 2 b 1 interacting with corresponding snap elements 2 d on the container. The mixing device is of a type, for example, which is described in more detail in EP 1 016 452 A2, in which a polymer, with which the mixing container has been pre-filled, is mixed under a vacuum with a monomer for the preparation of bone cement.

The container 2, which in the embodiment shown in the drawing has an air inlet aperture 2 c adjacent to the cap 2 b, is designed to enclose at least one and up to three ampoules. The embodiment shown in the drawing the container encloses two ampoules 3 a, 3 b.

Operatively connected to the removable cap 2 b is a holder 3, designed to hold the ampoules 3 a, 3 b in a predefined position in the container 2 by means of a positively interlocking engagement around the necks 3 a 1, 3 b 1 of the ampoules 3 a, 3 b.

Also operatively connected to the openable cap 2 b are manually actuatable elements for opening the ampoules 3 a, 3 b. The said elements comprise a knob 4, which is in threaded engagement 4 a with a rod 5 carried through cap 2 b. At its remote end, the rod 5 has a holder 5 a for metal spikes 6 pointing towards the base 3 a 2, 3 b 2 of each ampoule. For the holder 5 a there is a guide 2 e of a complementary shape to that of the holder 5 a.

The distance of the metal spikes 6 from the base 3 a 2, 3 b 2 of each ampoule is adjustable. It will be appreciated that manually turning the knob 4 reduces the distance between the spikes 6 and the base 3 a 2, 3 b 2 of each ampoule until the spikes 6 ultimately penetrate the bases of the ampoules. An identical distance between the spikes and the base 3 a 2, 3 b 2 of each ampoule naturally produces simultaneous penetration, but by selecting a different distance between the spikes 6 and the base 3 a 2, 3 b 2 of each respective ampoule the ampoule bases will be audibly penetrated at different times in succession. FIG. 3 illustrates with a dashed line a spike 6′ which, for example, has been assigned a shorter distance from the base of the ampoule than the other spike 6.

Also worth noting from FIGS. 1 and 3 is a filter 7, designed to prevent glass splinters from the ampoules 3 a, 3 b reaching the delivery duct 2 a 1 of the connection 2 a.

As will be apparent from the description above, the device according to the invention is made up of few parts and has a particularly simple and reliable method of handling. When it is to be used, the requisite number of ampoules 3 a, 3 b for the desired quantity of bone cement are inserted into the holder 3, which holds them fast at the necks 3 a 1, 3 b 1, there being a distance between the spikes 6 and the base 3 a 2, 3 b 2 of each ampoule large enough to prevent accidental penetration. The ampoules 3 a, 3 b thus fixed to the cap 2 b are inserted into the container 2 far enough for the user to distinctly hear the cap 2 b snap tight to the container 2.

The delivery device 1 is then connected by its connection 2 a to the mixing vessel where, under the vacuum there prevailing, air can flow through the container 2 via the air inlet: aperture 2 c.

Turning the knob 4 causes the ampoules to be successively penetrated, preferably audibly, and the monomer contained in the ampoules is carried down into the mixing vessel by the air flowing through the container 2.

The further process of preparing bone cement is well-known and will therefore not be further explained here. 

1. Delivery device fir a monomers comprising: an elongate container designed to enclose at least one ampoule containing the monomer, the container at one end being provided with a connection for delivering the monomer to a mixing device, pre-filled with a polymer, for the preparation of bone cement under vacuum, and at its other end having a cap and in the container wall, at least one air inlet aperture and manually actuatable elements for opening at least one ampoule wherein the cap is removable from the container and has holding elements designed by means of a positively interlocking engagement to hold fast an ampoule neck inserted into the holding elements, and wherein the said opening element includes a knob, in threaded engagement with a draw rod, the remote end of which extends past the base of the said at least one ampoule and has a spike pointing towards the base of each at least one ampoule, it being possible to make the spike penetrate the base by turning the knob.
 2. Device according to claim 1, wherein the container has the capacity to enclose a maximum of three ampoules and wherein there is a number of spikes corresponding to the number of ampoules and connected to the draw rod, the distance of which spikes from the base of each ampoule is adjustable.
 3. Device according to claim 1, wherein there are interacting snap elements between the container and the cap thereof.
 4. Device according to claim 2, wherein there are interacting snap elements between the container and the cap thereof. 